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Three-dimensional display systems
Published in John P. Dakin, Robert G. W. Brown, Handbook of Optoelectronics, 2017
Okoshi [40] notes that problems with parallax barriers include the reduced brightness due to blocking the light from pixels, reflection from the glass surface of the parallax barrier and the design of the parallax apertures to avoid diffraction problems. However, these disadvantages have been addressed and recent LCD-based designs overcome the first two problems by using bright light sources and antireflection-coated optics. The result is parallax barriers are now widely used for two-view displays such as described [62,63] and illustrated in Figure 9.13.
3DTV Technology and Standardization
Published in Hassnaa Moustafa, Sherali Zeadally, Media Networks: Architectures, Applications, and Standards, 2016
More recently, 3D-capable mobile devices were introduced to the market. These glasses-free systems are often called auto-stereoscopic displays although in this case, they are based on a stereoscopic video format. The technology generally implemented is a grid placed over the screen, called the parallax barrier. When activated, this barrier prevents the eyes of the user from viewing all the pixels of the display such as depicted in Figure 5.1.
Fabrication technology for light field reconstruction in glasses-free 3D display
Published in Journal of Information Display, 2023
Fengbin Zhou, Wen Qiao, Linsen Chen
Parallax barrier-based 3D display was first developed by F. E. Ives in 1902 [3]. A shaded screen was adopted in front of a screen to orient the emitted light and create parallax, as shown in Figure 2(a) [4]. Although the parallax barrier has been applied to 3D display owing to its advantages of easily accessible fabrication and low cost, low light efficiency hinders its further development. Cylindrical lens-based 3D display was then employed, as shown in Figure 2(b), to improve the light efficiency. Similar to the parallax barrier-based 3D display, the direction of light is modulated by the cylindrical lens, forming multiple views in space (Figure 1(b)). Based on binocular disparity, the 3D images can be formed in the human brain. Despite the limited motion parallax provided by cylindrical lens, it is the technology that is closest to the industrial sector. Most recently, Huang et al. used a head tracking system to expand the FOV to 56.5°, as shown in Figure 2(c) [5].
2D/3D switchable displays through PDLC reverse mode parallax barrier
Published in Liquid Crystals, 2018
Giuseppe Chidichimo, Amerigo Beneduci, Vito Maltese, Sante Cospito, Antonio Tursi, Paolo Tassini, Giuseppe Pandolfi
The 3D display technology is older than 25 years. A first prototype dated back to 1992 [1] was based on an optical system able to combine the images coming from two liquid crystals displays (LCDs) mounted at 90° in such a way that the image from the first LCD is received by one eye and that from the second orthogonal LCD is received by the other eye. Such a set-up was too large and expensive for the mass market and, for this reason, efforts were made to produce single panel 3D display [2] based on the application of parallax barrier methods [3]. Parallax barriers consist of thin-material layers bringing on their surface vertical opaque strips, intercalated between analogous transparent strips. The interposition of a parallax barriers between the viewer and a 2D display screen can shift the image from 2D to 3D, when the width and separation distance of strips are opportunely designed taking into account the size of the LCD display pixels, the distance between the LCD display and the barrier, the distance between viewer eyes and finally, the viewing distance. This is simply due to the fact that the parallax barrier directs the light coming from adjacent pixels to each eye. After some year from the appearance on the market of the first 3D parallax barrier displays, it was understood that the possibility to change, on viewer demand, the image perception from 2D to 3D and vice-versa was a significant improvement of the parallax barrier display technology [4]. This for two main reasons: first of all, it must be considered that the presence of the parallax barrier somewhat attenuates the light coming from the LCD. Secondly, the viewer must keep a defined position with respect to the display screen in order to receive a good 3D image. Thus, it can be very much appreciated to switch from the 3D vision to the 2D one, just to have the possibility to change the position according to personal needs. Since at the beginning the dark/clear alternate effect was achieved by use of a patterned retarder parallax barrier and the addition of a second polariser [5], the first 2D/3D switchable displays, consisted in the mechanical removing/inserting of the second polariser. Afterwards, in 2001 a first prototype of display that could be electronically switched between 2D and 3D modes was produced through the application of LC switchable polarisers. More recently, among the 3D image technologies based on parallax barriers [6], a promising new one, based on holographic optical elements (HOEs), was proposed as an efficient way for producing autostereoscopic 3D displays [7–9]. The conversion from a 2D to a 3D observation mode of the display is achieved by the HOEs which diffract the image on odd and even pixels directly to the right and left eyes of an observer. Different materials were proposed for realising the HOEs, among which dichromated gelatine [7] and holographic polymer-dispersed liquid crystals (H-PDLCs) [9]. In the latter case, Wang et al. designed a switchable image splitter based on varied-line-spacing H-PDLC (VLS H-PDLC) gratings able to increase the viewing angle of the observer and to allow the movement of the eyes of the observer across a distance of about 38 mm. Application of an external alternating-current voltage of about 80 V allows to switch the VLS H-PDLC grating between 2D and 3D modes [9].